//(c) 2006 Valerio Proietti (http://mad4milk.net). MIT-style license.
//moo.fx.js - depends on prototype.js OR prototype.lite.js
//version 2.0

var Fx = fx = {};

Fx.Base = function(){};
Fx.Base.prototype = {

    setOptions: function(options){
        this.options = Object.extend({
            onStart: function(){},
            onComplete: function(){},
            transition: Fx.Transitions.sineInOut,
            duration: 500,
            unit: 'px',
            wait: true,
            fps: 50
        }, options || {});
    },

    step: function(){
        var time = new Date().getTime();
        if (time < this.time + this.options.duration){
            this.cTime = time - this.time;
            this.setNow();
        } else {
            setTimeout(this.options.onComplete.bind(this, this.element), 10);
            this.clearTimer();
            this.now = this.to;
        }
        this.increase();
    },

    setNow: function(){
        this.now = this.compute(this.from, this.to);
    },

    compute: function(from, to){
        var change = to - from;
        return this.options.transition(this.cTime, from, change, this.options.duration);
    },

    clearTimer: function(){
        clearInterval(this.timer);
        this.timer = null;
        return this;
    },

    _start: function(from, to){
        if (!this.options.wait) this.clearTimer();
        if (this.timer) return;
        setTimeout(this.options.onStart.bind(this, this.element), 10);
        this.from = from;
        this.to = to;
        this.time = new Date().getTime();
        this.timer = setInterval(this.step.bind(this), Math.round(1000/this.options.fps));
        return this;
    },

    custom: function(from, to){
        return this._start(from, to);
    },

    set: function(to){
        this.now = to;
        this.increase();
        return this;
    },

    hide: function(){
        return this.set(0);
    },

    setStyle: function(e, p, v){
        if (p == 'opacity'){
            if (v == 0 && e.style.visibility != "hidden") e.style.visibility = "hidden";
            else if (e.style.visibility != "visible") e.style.visibility = "visible";
            if (window.ActiveXObject) e.style.filter = "alpha(opacity=" + v*100 + ")";
            e.style.opacity = v;
        } else e.style[p] = v+this.options.unit;
    },

    /* added by Jeffrey Sambells */
    stop: function(end){
        if (!this.timer) return this;
        clearTimeout(this.timer);
        clearInterval(this.timer);
        this.timer = null;
        return this;
    }

};

Fx.Style = Class.create();
Fx.Style.prototype = Object.extend(new Fx.Base(), {

    initialize: function(el, property, options){
        this.element = $(el);
        this.setOptions(options);
        this.property = property.camelize();
    },

    increase: function(){
        this.setStyle(this.element, this.property, this.now);
    }

});

Fx.Styles = Class.create();
Fx.Styles.prototype = Object.extend(new Fx.Base(), {

    initialize: function(el, options){
        this.element = $(el);
        this.setOptions(options);
        this.now = {};
    },

    setNow: function(){
        for (p in this.from) this.now[p] = this.compute(this.from[p], this.to[p]);
    },

    custom: function(obj){
        if (this.timer && this.options.wait) return;
        var from = {};
        var to = {};
        for (p in obj){
            from[p] = obj[p][0];
            to[p] = obj[p][1];
        }
        return this._start(from, to);
    },

    increase: function(){
        for (var p in this.now) this.setStyle(this.element, p, this.now[p]);
    }

});

//Transitions (c) 2003 Robert Penner (http://www.robertpenner.com/easing/), BSD License.

Fx.Transitions = {
    linear: function(t, b, c, d) { return c*t/d + b; },
    sineInOut: function(t, b, c, d) { return -c/2 * (Math.cos(Math.PI*t/d) - 1) + b; }
};